(a) Field of the Invention
The present invention relates to a trolley structure, and more particularly, to one that allows reliable transmission and reduced stand area for savings in production cost and space consumed.
(b) Description of the Prior Art
Usually a conventional trolley is provided with a fixed stand, which is not easy to carry and consumes too much space. Therefore, an improved structure is therefore introduced, which is retractable as illustrated in FIG. 7 of the accompanying drawings. The trolley comprises a main frame (A) and a retractable handlebar (B). The main frame (A) comprises a pair of rods (A1) at respective bottom ends of the main frame (A). A rotary wheel frame (A2) is inserted onto each rod (A1) to hold a wheel (A3). A gear (A4) is provided on the quarter of the outer circumference at the bottom of each wheel frame (A2) as illustrated in FIG. 8. A stand (C) is pivoted to the bottom of each rod (A1) and is connected with a telescopic rod (C1). Another end of the telescopic rod (C1) is connected to the handlebar (B). A U-shaped pivoting section (C2) is each provided on respective sides of the stand (C). One inner side of the pivoting section (C2) is provided with a gear (C3) to engage with the gear (A4) of the wheel base (A2) so that when the stand (C) is folded, the gear (C3) in the pivoting section (C2) of the stand (C) turns upwardly for 90 degrees while the gear (A4) of the wheel frame (A2) relatively rotates for a quarter of a turn. Meanwhile, the wheel frame (A2) turns for a quarter of a turn together with the gear (A4) for the wheel (A3) to be collapsed in flushed against the side age of the rod (A1). Accordingly, both the stand (C) and the wheels (A3) can be easily and synchronously collapsed.
However, the pivoting section (C2) of the stand (C) has to accommodate the rod (A1) of the main frame (A) to prevent the attempt of reducing the spacing between the stand (C) and the rod (A1). As a result the excessively large area of the stand (C) consumes too much space. Furthermore, the gear (A4) of the wheel frame (A2) for being disposed on the outer circumference prevents reliable engagement with the gear (C3) and even the teeth could easily break down to fail the turning.